1. Field of the Invention
The invention relates to a filter device for the physical elimination of microbes, suspended matter and solids from water.
2. Description of the Related Art
A filter device similar to that of this invention is known from U.S. Pat. No. 4,980,056. A disadvantage of this previously known theory, however, is that only one retentate discharge opening is provided. As a result, the fibres in the flow of water from the outside are not flushed in a defined manner and deposits adhere to a large number of the fibres.
In the further state of the art, reference is also made to U.S. Pat. No. 4,713,175, AS 4,676,896, U.S. Pat. No. 5,045,198 and DE 37 12 491 A1.
The invention has the purpose of improving the filter device mentioned in the introduction so that the water flow from a drinking water supply pipe can be sterilised and solids completely removed in a defined manner according to requirements.
With the invention this purpose is fulfilled by means of the features in the main claim. On the underside of the housing there are two outlets, one of which can be closed as required by means of a valve. The main flow passes through the hollow fibres and discharges from the outlet fitted with a valve. This flow is not filtered. If filtered water is required, the outlet fitted with a valve is closed. The water passes through the walls of the hollow-fibre membranes with defined pore size and flows out of the housing through the second outlet. The filter acts as a dead-end filter. This flow of permeate is free of solids and exhibits a bacterial concentration which is 7 logarithmic stages lower than the inflow. If no more sterilised water is required, the valve can be reopened. This terminates dead-end operation and the filter is automatically flushed by the main flow. No back flushing is required to clean the membrane. The filtration unit according to the invention can be mounted on any water tap.
The invention provides a filter unit for the physical elimination of microbes, suspended matter and solids from water, which comprises housing which has a filter insert made of from about 200 to about 10000 hollow-fibre membranes with a defined pore width of from about 0.001 to about 1.0 xcexcm and which can be mounted on a water tap with its top side, wherein the bottom side features separate outlets for filtered and unfiltered water and at least in the outlet for the unfiltered water a valve is fitted with which this outlet can be closed.
The filter insert features a perforated ring filled with hollow fibres, the hollow-fibre membranes being bonded with each other at their ends at the top and bottom sides of the filter insert and connected with the ring in such a way that only the openings of the hollow fibres remain as openings in the ring surfaces, so that the water to be treated can flow vertically through the hollow-fibre membranes and the permeate through the hollow-fibre walls to the outside of the hollow fibres.
The invention also provides a filter unit for the physical elimination of microbes, suspended matter and solids from water, which comprises a housing having a filtered water path and an unfiltered water path;
the housing having a top side having an inlet for unfiltered water; a bottom side having an outlet for filtered water from the filtered water path and a different outlet for unfiltered water from the unfiltered water path, which outlet for unfiltered water is fitted with a valve;
a filter insert inside of the housing, which filter insert comprises from about 200 to about 10000 hollow-fibre membranes having side walls with pores through the side walls, which pores have a pore width of from about 0.001 xcexcm to about 1.0 xcexcm; which hollow-fibre membranes have a length defining an open entrance end and an opposite open exit end thereof, which membranes extend along their length such that the open entrance end of each membrane is positioned adjacent to the top side of the housing in fluid communication with the inlet, and the open exit end of each membrane is positioned adjacent to the bottom side of the housing in fluid communication with the outlet for unfiltered water;
the unfiltered water path extending from the inlet through the length of the hollow-fibre membranes, through an unfiltered water conduit and then out the outlet for unfiltered water;
the filtered water path extending from the inlet thorough a part of the length of the hollow-fibre membranes, through the side wall pores, through a filtered water conduit and then out the outlet for filtered water.
The filter insert comprises a perforated ring filled with the hollow-fibre membranes, hollow-fibre membranes being bonded with each other at their open entrance ends and open exit ends and connected with the ring such that only the open ends of the hollow fibres remain as openings in the ring surfaces, so that water to be treated can flow through the hollow-fibre membranes and the permeate through the walls.